gdb/
[deliverable/binutils-gdb.git] / gdb / infcall.c
1 /* Perform an inferior function call, for GDB, the GNU debugger.
2
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
5 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22 #include "defs.h"
23 #include "breakpoint.h"
24 #include "tracepoint.h"
25 #include "target.h"
26 #include "regcache.h"
27 #include "inferior.h"
28 #include "gdb_assert.h"
29 #include "block.h"
30 #include "gdbcore.h"
31 #include "language.h"
32 #include "objfiles.h"
33 #include "gdbcmd.h"
34 #include "command.h"
35 #include "gdb_string.h"
36 #include "infcall.h"
37 #include "dummy-frame.h"
38 #include "ada-lang.h"
39 #include "gdbthread.h"
40 #include "exceptions.h"
41
42 /* If we can't find a function's name from its address,
43 we print this instead. */
44 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
45 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
46 + 2 * sizeof (CORE_ADDR))
47
48 /* NOTE: cagney/2003-04-16: What's the future of this code?
49
50 GDB needs an asynchronous expression evaluator, that means an
51 asynchronous inferior function call implementation, and that in
52 turn means restructuring the code so that it is event driven. */
53
54 /* How you should pass arguments to a function depends on whether it
55 was defined in K&R style or prototype style. If you define a
56 function using the K&R syntax that takes a `float' argument, then
57 callers must pass that argument as a `double'. If you define the
58 function using the prototype syntax, then you must pass the
59 argument as a `float', with no promotion.
60
61 Unfortunately, on certain older platforms, the debug info doesn't
62 indicate reliably how each function was defined. A function type's
63 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
64 defined in prototype style. When calling a function whose
65 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
66 decide what to do.
67
68 For modern targets, it is proper to assume that, if the prototype
69 flag is clear, that can be trusted: `float' arguments should be
70 promoted to `double'. For some older targets, if the prototype
71 flag is clear, that doesn't tell us anything. The default is to
72 trust the debug information; the user can override this behavior
73 with "set coerce-float-to-double 0". */
74
75 static int coerce_float_to_double_p = 1;
76 static void
77 show_coerce_float_to_double_p (struct ui_file *file, int from_tty,
78 struct cmd_list_element *c, const char *value)
79 {
80 fprintf_filtered (file,
81 _("Coercion of floats to doubles "
82 "when calling functions is %s.\n"),
83 value);
84 }
85
86 /* This boolean tells what gdb should do if a signal is received while
87 in a function called from gdb (call dummy). If set, gdb unwinds
88 the stack and restore the context to what as it was before the
89 call.
90
91 The default is to stop in the frame where the signal was received. */
92
93 int unwind_on_signal_p = 0;
94 static void
95 show_unwind_on_signal_p (struct ui_file *file, int from_tty,
96 struct cmd_list_element *c, const char *value)
97 {
98 fprintf_filtered (file,
99 _("Unwinding of stack if a signal is "
100 "received while in a call dummy is %s.\n"),
101 value);
102 }
103
104 /* This boolean tells what gdb should do if a std::terminate call is
105 made while in a function called from gdb (call dummy).
106 As the confines of a single dummy stack prohibit out-of-frame
107 handlers from handling a raised exception, and as out-of-frame
108 handlers are common in C++, this can lead to no handler being found
109 by the unwinder, and a std::terminate call. This is a false positive.
110 If set, gdb unwinds the stack and restores the context to what it
111 was before the call.
112
113 The default is to unwind the frame if a std::terminate call is
114 made. */
115
116 static int unwind_on_terminating_exception_p = 1;
117
118 static void
119 show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty,
120 struct cmd_list_element *c,
121 const char *value)
122
123 {
124 fprintf_filtered (file,
125 _("Unwind stack if a C++ exception is "
126 "unhandled while in a call dummy is %s.\n"),
127 value);
128 }
129
130 /* Perform the standard coercions that are specified
131 for arguments to be passed to C or Ada functions.
132
133 If PARAM_TYPE is non-NULL, it is the expected parameter type.
134 IS_PROTOTYPED is non-zero if the function declaration is prototyped.
135 SP is the stack pointer were additional data can be pushed (updating
136 its value as needed). */
137
138 static struct value *
139 value_arg_coerce (struct gdbarch *gdbarch, struct value *arg,
140 struct type *param_type, int is_prototyped, CORE_ADDR *sp)
141 {
142 const struct builtin_type *builtin = builtin_type (gdbarch);
143 struct type *arg_type = check_typedef (value_type (arg));
144 struct type *type
145 = param_type ? check_typedef (param_type) : arg_type;
146
147 /* Perform any Ada-specific coercion first. */
148 if (current_language->la_language == language_ada)
149 arg = ada_convert_actual (arg, type);
150
151 /* Force the value to the target if we will need its address. At
152 this point, we could allocate arguments on the stack instead of
153 calling malloc if we knew that their addresses would not be
154 saved by the called function. */
155 arg = value_coerce_to_target (arg);
156
157 switch (TYPE_CODE (type))
158 {
159 case TYPE_CODE_REF:
160 {
161 struct value *new_value;
162
163 if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
164 return value_cast_pointers (type, arg);
165
166 /* Cast the value to the reference's target type, and then
167 convert it back to a reference. This will issue an error
168 if the value was not previously in memory - in some cases
169 we should clearly be allowing this, but how? */
170 new_value = value_cast (TYPE_TARGET_TYPE (type), arg);
171 new_value = value_ref (new_value);
172 return new_value;
173 }
174 case TYPE_CODE_INT:
175 case TYPE_CODE_CHAR:
176 case TYPE_CODE_BOOL:
177 case TYPE_CODE_ENUM:
178 /* If we don't have a prototype, coerce to integer type if necessary. */
179 if (!is_prototyped)
180 {
181 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
182 type = builtin->builtin_int;
183 }
184 /* Currently all target ABIs require at least the width of an integer
185 type for an argument. We may have to conditionalize the following
186 type coercion for future targets. */
187 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
188 type = builtin->builtin_int;
189 break;
190 case TYPE_CODE_FLT:
191 if (!is_prototyped && coerce_float_to_double_p)
192 {
193 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_double))
194 type = builtin->builtin_double;
195 else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin->builtin_double))
196 type = builtin->builtin_long_double;
197 }
198 break;
199 case TYPE_CODE_FUNC:
200 type = lookup_pointer_type (type);
201 break;
202 case TYPE_CODE_ARRAY:
203 /* Arrays are coerced to pointers to their first element, unless
204 they are vectors, in which case we want to leave them alone,
205 because they are passed by value. */
206 if (current_language->c_style_arrays)
207 if (!TYPE_VECTOR (type))
208 type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
209 break;
210 case TYPE_CODE_UNDEF:
211 case TYPE_CODE_PTR:
212 case TYPE_CODE_STRUCT:
213 case TYPE_CODE_UNION:
214 case TYPE_CODE_VOID:
215 case TYPE_CODE_SET:
216 case TYPE_CODE_RANGE:
217 case TYPE_CODE_STRING:
218 case TYPE_CODE_BITSTRING:
219 case TYPE_CODE_ERROR:
220 case TYPE_CODE_MEMBERPTR:
221 case TYPE_CODE_METHODPTR:
222 case TYPE_CODE_METHOD:
223 case TYPE_CODE_COMPLEX:
224 default:
225 break;
226 }
227
228 return value_cast (type, arg);
229 }
230
231 /* Return the return type of a function with its first instruction exactly at
232 the PC address. Return NULL otherwise. */
233
234 static struct type *
235 find_function_return_type (CORE_ADDR pc)
236 {
237 struct symbol *sym = find_pc_function (pc);
238
239 if (sym != NULL && BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) == pc
240 && SYMBOL_TYPE (sym) != NULL)
241 return TYPE_TARGET_TYPE (SYMBOL_TYPE (sym));
242
243 return NULL;
244 }
245
246 /* Determine a function's address and its return type from its value.
247 Calls error() if the function is not valid for calling. */
248
249 CORE_ADDR
250 find_function_addr (struct value *function, struct type **retval_type)
251 {
252 struct type *ftype = check_typedef (value_type (function));
253 struct gdbarch *gdbarch = get_type_arch (ftype);
254 struct type *value_type = NULL;
255 /* Initialize it just to avoid a GCC false warning. */
256 CORE_ADDR funaddr = 0;
257
258 /* If it's a member function, just look at the function
259 part of it. */
260
261 /* Determine address to call. */
262 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
263 || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
264 funaddr = value_address (function);
265 else if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
266 {
267 funaddr = value_as_address (function);
268 ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
269 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
270 || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
271 funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr,
272 &current_target);
273 }
274 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
275 || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
276 {
277 value_type = TYPE_TARGET_TYPE (ftype);
278
279 if (TYPE_GNU_IFUNC (ftype))
280 {
281 funaddr = gnu_ifunc_resolve_addr (gdbarch, funaddr);
282
283 /* Skip querying the function symbol if no RETVAL_TYPE has been
284 asked for. */
285 if (retval_type)
286 value_type = find_function_return_type (funaddr);
287 }
288 }
289 else if (TYPE_CODE (ftype) == TYPE_CODE_INT)
290 {
291 /* Handle the case of functions lacking debugging info.
292 Their values are characters since their addresses are char. */
293 if (TYPE_LENGTH (ftype) == 1)
294 funaddr = value_as_address (value_addr (function));
295 else
296 {
297 /* Handle function descriptors lacking debug info. */
298 int found_descriptor = 0;
299
300 funaddr = 0; /* pacify "gcc -Werror" */
301 if (VALUE_LVAL (function) == lval_memory)
302 {
303 CORE_ADDR nfunaddr;
304
305 funaddr = value_as_address (value_addr (function));
306 nfunaddr = funaddr;
307 funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr,
308 &current_target);
309 if (funaddr != nfunaddr)
310 found_descriptor = 1;
311 }
312 if (!found_descriptor)
313 /* Handle integer used as address of a function. */
314 funaddr = (CORE_ADDR) value_as_long (function);
315 }
316 }
317 else
318 error (_("Invalid data type for function to be called."));
319
320 if (retval_type != NULL)
321 *retval_type = value_type;
322 return funaddr + gdbarch_deprecated_function_start_offset (gdbarch);
323 }
324
325 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
326 function returns to. */
327
328 static CORE_ADDR
329 push_dummy_code (struct gdbarch *gdbarch,
330 CORE_ADDR sp, CORE_ADDR funaddr,
331 struct value **args, int nargs,
332 struct type *value_type,
333 CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
334 struct regcache *regcache)
335 {
336 gdb_assert (gdbarch_push_dummy_code_p (gdbarch));
337
338 return gdbarch_push_dummy_code (gdbarch, sp, funaddr,
339 args, nargs, value_type, real_pc, bp_addr,
340 regcache);
341 }
342
343 /* Fetch the name of the function at FUNADDR.
344 This is used in printing an error message for call_function_by_hand.
345 BUF is used to print FUNADDR in hex if the function name cannot be
346 determined. It must be large enough to hold formatted result of
347 RAW_FUNCTION_ADDRESS_FORMAT. */
348
349 static const char *
350 get_function_name (CORE_ADDR funaddr, char *buf, int buf_size)
351 {
352 {
353 struct symbol *symbol = find_pc_function (funaddr);
354
355 if (symbol)
356 return SYMBOL_PRINT_NAME (symbol);
357 }
358
359 {
360 /* Try the minimal symbols. */
361 struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr);
362
363 if (msymbol)
364 return SYMBOL_PRINT_NAME (msymbol);
365 }
366
367 {
368 char *tmp = xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT),
369 hex_string (funaddr));
370
371 gdb_assert (strlen (tmp) + 1 <= buf_size);
372 strcpy (buf, tmp);
373 xfree (tmp);
374 return buf;
375 }
376 }
377
378 /* Subroutine of call_function_by_hand to simplify it.
379 Start up the inferior and wait for it to stop.
380 Return the exception if there's an error, or an exception with
381 reason >= 0 if there's no error.
382
383 This is done inside a TRY_CATCH so the caller needn't worry about
384 thrown errors. The caller should rethrow if there's an error. */
385
386 static struct gdb_exception
387 run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc)
388 {
389 volatile struct gdb_exception e;
390 int saved_async = 0;
391 int saved_in_infcall = call_thread->control.in_infcall;
392 ptid_t call_thread_ptid = call_thread->ptid;
393 char *saved_target_shortname = xstrdup (target_shortname);
394
395 call_thread->control.in_infcall = 1;
396
397 clear_proceed_status ();
398
399 disable_watchpoints_before_interactive_call_start ();
400
401 /* We want stop_registers, please... */
402 call_thread->control.proceed_to_finish = 1;
403
404 if (target_can_async_p ())
405 saved_async = target_async_mask (0);
406
407 TRY_CATCH (e, RETURN_MASK_ALL)
408 proceed (real_pc, TARGET_SIGNAL_0, 0);
409
410 /* At this point the current thread may have changed. Refresh
411 CALL_THREAD as it could be invalid if its thread has exited. */
412 call_thread = find_thread_ptid (call_thread_ptid);
413
414 /* Don't restore the async mask if the target has changed,
415 saved_async is for the original target. */
416 if (saved_async
417 && strcmp (saved_target_shortname, target_shortname) == 0)
418 target_async_mask (saved_async);
419
420 enable_watchpoints_after_interactive_call_stop ();
421
422 /* Call breakpoint_auto_delete on the current contents of the bpstat
423 of inferior call thread.
424 If all error()s out of proceed ended up calling normal_stop
425 (and perhaps they should; it already does in the special case
426 of error out of resume()), then we wouldn't need this. */
427 if (e.reason < 0)
428 {
429 if (call_thread != NULL)
430 breakpoint_auto_delete (call_thread->control.stop_bpstat);
431 }
432
433 if (call_thread != NULL)
434 call_thread->control.in_infcall = saved_in_infcall;
435
436 xfree (saved_target_shortname);
437
438 return e;
439 }
440
441 /* A cleanup function that calls delete_std_terminate_breakpoint. */
442 static void
443 cleanup_delete_std_terminate_breakpoint (void *ignore)
444 {
445 delete_std_terminate_breakpoint ();
446 }
447
448 /* All this stuff with a dummy frame may seem unnecessarily complicated
449 (why not just save registers in GDB?). The purpose of pushing a dummy
450 frame which looks just like a real frame is so that if you call a
451 function and then hit a breakpoint (get a signal, etc), "backtrace"
452 will look right. Whether the backtrace needs to actually show the
453 stack at the time the inferior function was called is debatable, but
454 it certainly needs to not display garbage. So if you are contemplating
455 making dummy frames be different from normal frames, consider that. */
456
457 /* Perform a function call in the inferior.
458 ARGS is a vector of values of arguments (NARGS of them).
459 FUNCTION is a value, the function to be called.
460 Returns a value representing what the function returned.
461 May fail to return, if a breakpoint or signal is hit
462 during the execution of the function.
463
464 ARGS is modified to contain coerced values. */
465
466 struct value *
467 call_function_by_hand (struct value *function, int nargs, struct value **args)
468 {
469 CORE_ADDR sp;
470 struct type *values_type, *target_values_type;
471 unsigned char struct_return = 0, lang_struct_return = 0;
472 CORE_ADDR struct_addr = 0;
473 struct infcall_control_state *inf_status;
474 struct cleanup *inf_status_cleanup;
475 struct infcall_suspend_state *caller_state;
476 CORE_ADDR funaddr;
477 CORE_ADDR real_pc;
478 struct type *ftype = check_typedef (value_type (function));
479 CORE_ADDR bp_addr;
480 struct frame_id dummy_id;
481 struct cleanup *args_cleanup;
482 struct frame_info *frame;
483 struct gdbarch *gdbarch;
484 struct cleanup *terminate_bp_cleanup;
485 ptid_t call_thread_ptid;
486 struct gdb_exception e;
487 char name_buf[RAW_FUNCTION_ADDRESS_SIZE];
488
489 if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
490 ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
491
492 if (!target_has_execution)
493 noprocess ();
494
495 if (get_traceframe_number () >= 0)
496 error (_("May not call functions while looking at trace frames."));
497
498 frame = get_current_frame ();
499 gdbarch = get_frame_arch (frame);
500
501 if (!gdbarch_push_dummy_call_p (gdbarch))
502 error (_("This target does not support function calls."));
503
504 /* A cleanup for the inferior status.
505 This is only needed while we're preparing the inferior function call. */
506 inf_status = save_infcall_control_state ();
507 inf_status_cleanup
508 = make_cleanup_restore_infcall_control_state (inf_status);
509
510 /* Save the caller's registers and other state associated with the
511 inferior itself so that they can be restored once the
512 callee returns. To allow nested calls the registers are (further
513 down) pushed onto a dummy frame stack. Include a cleanup (which
514 is tossed once the regcache has been pushed). */
515 caller_state = save_infcall_suspend_state ();
516 make_cleanup_restore_infcall_suspend_state (caller_state);
517
518 /* Ensure that the initial SP is correctly aligned. */
519 {
520 CORE_ADDR old_sp = get_frame_sp (frame);
521
522 if (gdbarch_frame_align_p (gdbarch))
523 {
524 sp = gdbarch_frame_align (gdbarch, old_sp);
525 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
526 ABIs, a function can use memory beyond the inner most stack
527 address. AMD64 called that region the "red zone". Skip at
528 least the "red zone" size before allocating any space on
529 the stack. */
530 if (gdbarch_inner_than (gdbarch, 1, 2))
531 sp -= gdbarch_frame_red_zone_size (gdbarch);
532 else
533 sp += gdbarch_frame_red_zone_size (gdbarch);
534 /* Still aligned? */
535 gdb_assert (sp == gdbarch_frame_align (gdbarch, sp));
536 /* NOTE: cagney/2002-09-18:
537
538 On a RISC architecture, a void parameterless generic dummy
539 frame (i.e., no parameters, no result) typically does not
540 need to push anything the stack and hence can leave SP and
541 FP. Similarly, a frameless (possibly leaf) function does
542 not push anything on the stack and, hence, that too can
543 leave FP and SP unchanged. As a consequence, a sequence of
544 void parameterless generic dummy frame calls to frameless
545 functions will create a sequence of effectively identical
546 frames (SP, FP and TOS and PC the same). This, not
547 suprisingly, results in what appears to be a stack in an
548 infinite loop --- when GDB tries to find a generic dummy
549 frame on the internal dummy frame stack, it will always
550 find the first one.
551
552 To avoid this problem, the code below always grows the
553 stack. That way, two dummy frames can never be identical.
554 It does burn a few bytes of stack but that is a small price
555 to pay :-). */
556 if (sp == old_sp)
557 {
558 if (gdbarch_inner_than (gdbarch, 1, 2))
559 /* Stack grows down. */
560 sp = gdbarch_frame_align (gdbarch, old_sp - 1);
561 else
562 /* Stack grows up. */
563 sp = gdbarch_frame_align (gdbarch, old_sp + 1);
564 }
565 /* SP may have underflown address zero here from OLD_SP. Memory access
566 functions will probably fail in such case but that is a target's
567 problem. */
568 }
569 else
570 /* FIXME: cagney/2002-09-18: Hey, you loose!
571
572 Who knows how badly aligned the SP is!
573
574 If the generic dummy frame ends up empty (because nothing is
575 pushed) GDB won't be able to correctly perform back traces.
576 If a target is having trouble with backtraces, first thing to
577 do is add FRAME_ALIGN() to the architecture vector. If that
578 fails, try dummy_id().
579
580 If the ABI specifies a "Red Zone" (see the doco) the code
581 below will quietly trash it. */
582 sp = old_sp;
583 }
584
585 funaddr = find_function_addr (function, &values_type);
586 if (!values_type)
587 values_type = builtin_type (gdbarch)->builtin_int;
588
589 CHECK_TYPEDEF (values_type);
590
591 /* Are we returning a value using a structure return (passing a
592 hidden argument pointing to storage) or a normal value return?
593 There are two cases: language-mandated structure return and
594 target ABI structure return. The variable STRUCT_RETURN only
595 describes the latter. The language version is handled by passing
596 the return location as the first parameter to the function,
597 even preceding "this". This is different from the target
598 ABI version, which is target-specific; for instance, on ia64
599 the first argument is passed in out0 but the hidden structure
600 return pointer would normally be passed in r8. */
601
602 if (language_pass_by_reference (values_type))
603 {
604 lang_struct_return = 1;
605
606 /* Tell the target specific argument pushing routine not to
607 expect a value. */
608 target_values_type = builtin_type (gdbarch)->builtin_void;
609 }
610 else
611 {
612 struct_return = using_struct_return (gdbarch,
613 value_type (function), values_type);
614 target_values_type = values_type;
615 }
616
617 /* Determine the location of the breakpoint (and possibly other
618 stuff) that the called function will return to. The SPARC, for a
619 function returning a structure or union, needs to make space for
620 not just the breakpoint but also an extra word containing the
621 size (?) of the structure being passed. */
622
623 /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
624 is no need to write that out. */
625
626 switch (gdbarch_call_dummy_location (gdbarch))
627 {
628 case ON_STACK:
629 sp = push_dummy_code (gdbarch, sp, funaddr,
630 args, nargs, target_values_type,
631 &real_pc, &bp_addr, get_current_regcache ());
632 break;
633 case AT_ENTRY_POINT:
634 {
635 CORE_ADDR dummy_addr;
636
637 real_pc = funaddr;
638 dummy_addr = entry_point_address ();
639 /* A call dummy always consists of just a single breakpoint, so
640 its address is the same as the address of the dummy. */
641 bp_addr = dummy_addr;
642 break;
643 }
644 case AT_SYMBOL:
645 /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
646 address is the location where the breakpoint should be
647 placed. Once all targets are using the overhauled frame code
648 this can be deleted - ON_STACK is a better option. */
649 {
650 struct minimal_symbol *sym;
651 CORE_ADDR dummy_addr;
652
653 sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL);
654 real_pc = funaddr;
655 if (sym)
656 {
657 dummy_addr = SYMBOL_VALUE_ADDRESS (sym);
658 /* Make certain that the address points at real code, and not
659 a function descriptor. */
660 dummy_addr = gdbarch_convert_from_func_ptr_addr (gdbarch,
661 dummy_addr,
662 &current_target);
663 }
664 else
665 dummy_addr = entry_point_address ();
666 /* A call dummy always consists of just a single breakpoint,
667 so it's address is the same as the address of the dummy. */
668 bp_addr = dummy_addr;
669 break;
670 }
671 default:
672 internal_error (__FILE__, __LINE__, _("bad switch"));
673 }
674
675 if (nargs < TYPE_NFIELDS (ftype))
676 error (_("Too few arguments in function call."));
677
678 {
679 int i;
680
681 for (i = nargs - 1; i >= 0; i--)
682 {
683 int prototyped;
684 struct type *param_type;
685
686 /* FIXME drow/2002-05-31: Should just always mark methods as
687 prototyped. Can we respect TYPE_VARARGS? Probably not. */
688 if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
689 prototyped = 1;
690 else if (i < TYPE_NFIELDS (ftype))
691 prototyped = TYPE_PROTOTYPED (ftype);
692 else
693 prototyped = 0;
694
695 if (i < TYPE_NFIELDS (ftype))
696 param_type = TYPE_FIELD_TYPE (ftype, i);
697 else
698 param_type = NULL;
699
700 args[i] = value_arg_coerce (gdbarch, args[i],
701 param_type, prototyped, &sp);
702
703 if (param_type != NULL && language_pass_by_reference (param_type))
704 args[i] = value_addr (args[i]);
705 }
706 }
707
708 /* Reserve space for the return structure to be written on the
709 stack, if necessary. Make certain that the value is correctly
710 aligned. */
711
712 if (struct_return || lang_struct_return)
713 {
714 int len = TYPE_LENGTH (values_type);
715
716 if (gdbarch_inner_than (gdbarch, 1, 2))
717 {
718 /* Stack grows downward. Align STRUCT_ADDR and SP after
719 making space for the return value. */
720 sp -= len;
721 if (gdbarch_frame_align_p (gdbarch))
722 sp = gdbarch_frame_align (gdbarch, sp);
723 struct_addr = sp;
724 }
725 else
726 {
727 /* Stack grows upward. Align the frame, allocate space, and
728 then again, re-align the frame??? */
729 if (gdbarch_frame_align_p (gdbarch))
730 sp = gdbarch_frame_align (gdbarch, sp);
731 struct_addr = sp;
732 sp += len;
733 if (gdbarch_frame_align_p (gdbarch))
734 sp = gdbarch_frame_align (gdbarch, sp);
735 }
736 }
737
738 if (lang_struct_return)
739 {
740 struct value **new_args;
741
742 /* Add the new argument to the front of the argument list. */
743 new_args = xmalloc (sizeof (struct value *) * (nargs + 1));
744 new_args[0] = value_from_pointer (lookup_pointer_type (values_type),
745 struct_addr);
746 memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs);
747 args = new_args;
748 nargs++;
749 args_cleanup = make_cleanup (xfree, args);
750 }
751 else
752 args_cleanup = make_cleanup (null_cleanup, NULL);
753
754 /* Create the dummy stack frame. Pass in the call dummy address as,
755 presumably, the ABI code knows where, in the call dummy, the
756 return address should be pointed. */
757 sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (),
758 bp_addr, nargs, args,
759 sp, struct_return, struct_addr);
760
761 do_cleanups (args_cleanup);
762
763 /* Set up a frame ID for the dummy frame so we can pass it to
764 set_momentary_breakpoint. We need to give the breakpoint a frame
765 ID so that the breakpoint code can correctly re-identify the
766 dummy breakpoint. */
767 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
768 saved as the dummy-frame TOS, and used by dummy_id to form
769 the frame ID's stack address. */
770 dummy_id = frame_id_build (sp, bp_addr);
771
772 /* Create a momentary breakpoint at the return address of the
773 inferior. That way it breaks when it returns. */
774
775 {
776 struct breakpoint *bpt;
777 struct symtab_and_line sal;
778
779 init_sal (&sal); /* initialize to zeroes */
780 sal.pspace = current_program_space;
781 sal.pc = bp_addr;
782 sal.section = find_pc_overlay (sal.pc);
783 /* Sanity. The exact same SP value is returned by
784 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
785 dummy_id to form the frame ID's stack address. */
786 bpt = set_momentary_breakpoint (gdbarch, sal, dummy_id, bp_call_dummy);
787 bpt->disposition = disp_del;
788 }
789
790 /* Create a breakpoint in std::terminate.
791 If a C++ exception is raised in the dummy-frame, and the
792 exception handler is (normally, and expected to be) out-of-frame,
793 the default C++ handler will (wrongly) be called in an inferior
794 function call. This is wrong, as an exception can be normally
795 and legally handled out-of-frame. The confines of the dummy frame
796 prevent the unwinder from finding the correct handler (or any
797 handler, unless it is in-frame). The default handler calls
798 std::terminate. This will kill the inferior. Assert that
799 terminate should never be called in an inferior function
800 call. Place a momentary breakpoint in the std::terminate function
801 and if triggered in the call, rewind. */
802 if (unwind_on_terminating_exception_p)
803 set_std_terminate_breakpoint ();
804
805 /* Everything's ready, push all the info needed to restore the
806 caller (and identify the dummy-frame) onto the dummy-frame
807 stack. */
808 dummy_frame_push (caller_state, &dummy_id);
809
810 /* Discard both inf_status and caller_state cleanups.
811 From this point on we explicitly restore the associated state
812 or discard it. */
813 discard_cleanups (inf_status_cleanup);
814
815 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
816 terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint,
817 NULL);
818
819 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
820 If you're looking to implement asynchronous dummy-frames, then
821 just below is the place to chop this function in two.. */
822
823 /* TP is invalid after run_inferior_call returns, so enclose this
824 in a block so that it's only in scope during the time it's valid. */
825 {
826 struct thread_info *tp = inferior_thread ();
827
828 /* Save this thread's ptid, we need it later but the thread
829 may have exited. */
830 call_thread_ptid = tp->ptid;
831
832 /* Run the inferior until it stops. */
833
834 e = run_inferior_call (tp, real_pc);
835 }
836
837 /* Rethrow an error if we got one trying to run the inferior. */
838
839 if (e.reason < 0)
840 {
841 const char *name = get_function_name (funaddr,
842 name_buf, sizeof (name_buf));
843
844 discard_infcall_control_state (inf_status);
845
846 /* We could discard the dummy frame here if the program exited,
847 but it will get garbage collected the next time the program is
848 run anyway. */
849
850 switch (e.reason)
851 {
852 case RETURN_ERROR:
853 throw_error (e.error, _("%s\n\
854 An error occurred while in a function called from GDB.\n\
855 Evaluation of the expression containing the function\n\
856 (%s) will be abandoned.\n\
857 When the function is done executing, GDB will silently stop."),
858 e.message, name);
859 case RETURN_QUIT:
860 default:
861 throw_exception (e);
862 }
863 }
864
865 /* If the program has exited, or we stopped at a different thread,
866 exit and inform the user. */
867
868 if (! target_has_execution)
869 {
870 const char *name = get_function_name (funaddr,
871 name_buf, sizeof (name_buf));
872
873 /* If we try to restore the inferior status,
874 we'll crash as the inferior is no longer running. */
875 discard_infcall_control_state (inf_status);
876
877 /* We could discard the dummy frame here given that the program exited,
878 but it will get garbage collected the next time the program is
879 run anyway. */
880
881 error (_("The program being debugged exited while in a function "
882 "called from GDB.\n"
883 "Evaluation of the expression containing the function\n"
884 "(%s) will be abandoned."),
885 name);
886 }
887
888 if (! ptid_equal (call_thread_ptid, inferior_ptid))
889 {
890 const char *name = get_function_name (funaddr,
891 name_buf, sizeof (name_buf));
892
893 /* We've switched threads. This can happen if another thread gets a
894 signal or breakpoint while our thread was running.
895 There's no point in restoring the inferior status,
896 we're in a different thread. */
897 discard_infcall_control_state (inf_status);
898 /* Keep the dummy frame record, if the user switches back to the
899 thread with the hand-call, we'll need it. */
900 if (stopped_by_random_signal)
901 error (_("\
902 The program received a signal in another thread while\n\
903 making a function call from GDB.\n\
904 Evaluation of the expression containing the function\n\
905 (%s) will be abandoned.\n\
906 When the function is done executing, GDB will silently stop."),
907 name);
908 else
909 error (_("\
910 The program stopped in another thread while making a function call from GDB.\n\
911 Evaluation of the expression containing the function\n\
912 (%s) will be abandoned.\n\
913 When the function is done executing, GDB will silently stop."),
914 name);
915 }
916
917 if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY)
918 {
919 const char *name = get_function_name (funaddr,
920 name_buf, sizeof (name_buf));
921
922 if (stopped_by_random_signal)
923 {
924 /* We stopped inside the FUNCTION because of a random
925 signal. Further execution of the FUNCTION is not
926 allowed. */
927
928 if (unwind_on_signal_p)
929 {
930 /* The user wants the context restored. */
931
932 /* We must get back to the frame we were before the
933 dummy call. */
934 dummy_frame_pop (dummy_id);
935
936 /* We also need to restore inferior status to that before the
937 dummy call. */
938 restore_infcall_control_state (inf_status);
939
940 /* FIXME: Insert a bunch of wrap_here; name can be very
941 long if it's a C++ name with arguments and stuff. */
942 error (_("\
943 The program being debugged was signaled while in a function called from GDB.\n\
944 GDB has restored the context to what it was before the call.\n\
945 To change this behavior use \"set unwindonsignal off\".\n\
946 Evaluation of the expression containing the function\n\
947 (%s) will be abandoned."),
948 name);
949 }
950 else
951 {
952 /* The user wants to stay in the frame where we stopped
953 (default).
954 Discard inferior status, we're not at the same point
955 we started at. */
956 discard_infcall_control_state (inf_status);
957
958 /* FIXME: Insert a bunch of wrap_here; name can be very
959 long if it's a C++ name with arguments and stuff. */
960 error (_("\
961 The program being debugged was signaled while in a function called from GDB.\n\
962 GDB remains in the frame where the signal was received.\n\
963 To change this behavior use \"set unwindonsignal on\".\n\
964 Evaluation of the expression containing the function\n\
965 (%s) will be abandoned.\n\
966 When the function is done executing, GDB will silently stop."),
967 name);
968 }
969 }
970
971 if (stop_stack_dummy == STOP_STD_TERMINATE)
972 {
973 /* We must get back to the frame we were before the dummy
974 call. */
975 dummy_frame_pop (dummy_id);
976
977 /* We also need to restore inferior status to that before
978 the dummy call. */
979 restore_infcall_control_state (inf_status);
980
981 error (_("\
982 The program being debugged entered a std::terminate call, most likely\n\
983 caused by an unhandled C++ exception. GDB blocked this call in order\n\
984 to prevent the program from being terminated, and has restored the\n\
985 context to its original state before the call.\n\
986 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
987 Evaluation of the expression containing the function (%s)\n\
988 will be abandoned."),
989 name);
990 }
991 else if (stop_stack_dummy == STOP_NONE)
992 {
993
994 /* We hit a breakpoint inside the FUNCTION.
995 Keep the dummy frame, the user may want to examine its state.
996 Discard inferior status, we're not at the same point
997 we started at. */
998 discard_infcall_control_state (inf_status);
999
1000 /* The following error message used to say "The expression
1001 which contained the function call has been discarded."
1002 It is a hard concept to explain in a few words. Ideally,
1003 GDB would be able to resume evaluation of the expression
1004 when the function finally is done executing. Perhaps
1005 someday this will be implemented (it would not be easy). */
1006 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
1007 a C++ name with arguments and stuff. */
1008 error (_("\
1009 The program being debugged stopped while in a function called from GDB.\n\
1010 Evaluation of the expression containing the function\n\
1011 (%s) will be abandoned.\n\
1012 When the function is done executing, GDB will silently stop."),
1013 name);
1014 }
1015
1016 /* The above code errors out, so ... */
1017 internal_error (__FILE__, __LINE__, _("... should not be here"));
1018 }
1019
1020 do_cleanups (terminate_bp_cleanup);
1021
1022 /* If we get here the called FUNCTION ran to completion,
1023 and the dummy frame has already been popped. */
1024
1025 {
1026 struct address_space *aspace = get_regcache_aspace (stop_registers);
1027 struct regcache *retbuf = regcache_xmalloc (gdbarch, aspace);
1028 struct cleanup *retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
1029 struct value *retval = NULL;
1030
1031 regcache_cpy_no_passthrough (retbuf, stop_registers);
1032
1033 /* Inferior call is successful. Restore the inferior status.
1034 At this stage, leave the RETBUF alone. */
1035 restore_infcall_control_state (inf_status);
1036
1037 /* Figure out the value returned by the function. */
1038 retval = allocate_value (values_type);
1039
1040 if (lang_struct_return)
1041 read_value_memory (retval, 0, 1, struct_addr,
1042 value_contents_raw (retval),
1043 TYPE_LENGTH (values_type));
1044 else if (TYPE_CODE (target_values_type) != TYPE_CODE_VOID)
1045 {
1046 /* If the function returns void, don't bother fetching the
1047 return value. */
1048 switch (gdbarch_return_value (gdbarch, value_type (function),
1049 target_values_type, NULL, NULL, NULL))
1050 {
1051 case RETURN_VALUE_REGISTER_CONVENTION:
1052 case RETURN_VALUE_ABI_RETURNS_ADDRESS:
1053 case RETURN_VALUE_ABI_PRESERVES_ADDRESS:
1054 gdbarch_return_value (gdbarch, value_type (function), values_type,
1055 retbuf, value_contents_raw (retval), NULL);
1056 break;
1057 case RETURN_VALUE_STRUCT_CONVENTION:
1058 read_value_memory (retval, 0, 1, struct_addr,
1059 value_contents_raw (retval),
1060 TYPE_LENGTH (values_type));
1061 break;
1062 }
1063 }
1064
1065 do_cleanups (retbuf_cleanup);
1066
1067 gdb_assert (retval);
1068 return retval;
1069 }
1070 }
1071 \f
1072
1073 /* Provide a prototype to silence -Wmissing-prototypes. */
1074 void _initialize_infcall (void);
1075
1076 void
1077 _initialize_infcall (void)
1078 {
1079 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
1080 &coerce_float_to_double_p, _("\
1081 Set coercion of floats to doubles when calling functions."), _("\
1082 Show coercion of floats to doubles when calling functions"), _("\
1083 Variables of type float should generally be converted to doubles before\n\
1084 calling an unprototyped function, and left alone when calling a prototyped\n\
1085 function. However, some older debug info formats do not provide enough\n\
1086 information to determine that a function is prototyped. If this flag is\n\
1087 set, GDB will perform the conversion for a function it considers\n\
1088 unprototyped.\n\
1089 The default is to perform the conversion.\n"),
1090 NULL,
1091 show_coerce_float_to_double_p,
1092 &setlist, &showlist);
1093
1094 add_setshow_boolean_cmd ("unwindonsignal", no_class,
1095 &unwind_on_signal_p, _("\
1096 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1097 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1098 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1099 is received while in a function called from gdb (call dummy). If set, gdb\n\
1100 unwinds the stack and restore the context to what as it was before the call.\n\
1101 The default is to stop in the frame where the signal was received."),
1102 NULL,
1103 show_unwind_on_signal_p,
1104 &setlist, &showlist);
1105
1106 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
1107 &unwind_on_terminating_exception_p, _("\
1108 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1109 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1110 _("\
1111 The unwind on terminating exception flag lets the user determine\n\
1112 what gdb should do if a std::terminate() call is made from the\n\
1113 default exception handler. If set, gdb unwinds the stack and restores\n\
1114 the context to what it was before the call. If unset, gdb allows the\n\
1115 std::terminate call to proceed.\n\
1116 The default is to unwind the frame."),
1117 NULL,
1118 show_unwind_on_terminating_exception_p,
1119 &setlist, &showlist);
1120
1121 }
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